Reported on Facebook today was that the surgery is being postponed until after Worlds. She's currently training with some kind of protective mask. They haven't fully decided on participating in Worlds, but it does look like they're going to try very hard to make it work... I hope their courage will last and I hope Nathalie isn't in too much pain...

PS: It may sound inappropriate, but the image of Natalie having a facial cast to go with her mummy costume kind of make me laugh. That must be considered as a huge step up to complet one's costume. -----seriously, take care, Natalie, and good luck!

It's blurry, but here's a pic of Nathalie & Fabian doing an interview in Nice. The angle and resolution make it difficult to tell what sort of shape Nathalie is in, but hopefully she's feeling well & both of them will have a great competition.

And ISU Figure Skating Facebook page also confirms that P/B will compete.

I've copied below the Mar 25 press release in the original French from the official 2012 Worlds website.
When I use Google Translate, it says (among other things) that Nathalie has received the green light to compete from a medical specialist; that she has trouble breathing and constant pain ... but that they look forward to being on the ice Wednesday night; that she has not decided whether to wear a protective mask in competition, and that their first workout tomorrow should provide more guidance.